From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f69.google.com (mail-oo1-f69.google.com [209.85.161.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A04C43815D8 for ; Wed, 25 Feb 2026 09:12:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772010774; cv=none; b=kygr7lv70xdq4xHf2BOBtc4lMSQMMiN3Q1GvKyOzKHIs3hz6Qp508nU5Ggl5i93dITHCFV6bcuOIwvYxo/sp48abALlmtlcEZK4p6JpFFUQwiMwcqavJyYN/aeblAk84W+4IyfOYWiYFuU97IbS7JXOmZU/soku/gqRAmZO2DfU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772010774; c=relaxed/simple; bh=Rj0WRPWI/1OZsyjrja5BPuIjb2XaIjOhtKO/MTD9LaU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=I1rV5ChInWWkbgFoJWziqCXPTDl8TQqOchG+iRVt4B6QwdlAYWnzY9/3tjK1IpSGG/WkW3ox/F7WdcutC7Cd0Emp9G7lJjgvZkxz2A9gP/LiZgVPTi0Yzk0JXo6KjshvWFcOtjdmyFvXOWYVPtUWM+CJIGXGmOXWqH8fWptI1ZM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f69.google.com with SMTP id 006d021491bc7-6798747187eso101814155eaf.1 for ; Wed, 25 Feb 2026 01:12:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772010769; x=1772615569; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=NQefKd/FMJZjNkjcfOMqZE28IH7UDte/+y3dOHKHDNQ=; b=NOId4944UoM7EGf0JRsfu2fpFjshQhlEtr7JKIaFSstBPudhIhhp/H5PO6gNbtwLxt Q2OnBNP8KBZ5S4Fuuap6woPkhYxQYwdp4/rUpPUxZdMWU13+DUrk0qRSKji0cKZQcMoP 5s2jJlCF6Kn1SfIbypMhF/b/lz9qDcOVHKWhu2pYwbN9HjQ4bYJ2TWUtjhWMK1sC3gKn XWV/w0oeIVdYKY5t9fjuwuFBeBNx9I8yLOE+JrlTLI7JM34aAvgDIdYHUKxLvzCYC93n RDjIP31EbnBZtIuP3huN9vLiFih9Ec3ZYsOAqBKWt9ZUjfzyNAx4tQvDaXJGu2cX5cGh DF2A== X-Forwarded-Encrypted: i=1; AJvYcCXFEcKoj7LIl8q/ylwskpOELEVcHeSTwkCjrh/IcR8JHx18/2jCtqqKDOESgRH2JQTVn4F5Ii5ga+Q9JTN0@vger.kernel.org X-Gm-Message-State: AOJu0YwUcIXrRpWvI5B23cu4/XX7Diom1dNKoumftKpYEXE3A18juhqT d7lUhHrjd6jzRYBPGCBY/yKxJx/J02gLNKmj3lS6EEoVDJds9KefwNNe+2PSbTkcpljyHyi/o4a o3GQ6AFVl/5t92WYvwoUgAYCjeCQqLDAWx3XK5r34APU3o46lVP7UksAYT3Y= Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:edc9:0:b0:679:94c0:117f with SMTP id 006d021491bc7-679c4267a48mr8234100eaf.23.1772010769450; Wed, 25 Feb 2026 01:12:49 -0800 (PST) Date: Wed, 25 Feb 2026 01:12:49 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <699ebd11.a00a0220.21906d.0005.GAE@google.com> Subject: [syzbot] [ext4?] INFO: task hung in filename_unlinkat From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: a95f71ad3e2e Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15cfc55a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=abe4fa590468dbfb dashboard link: https://syzkaller.appspot.com/bug?extid=1659aaaaa8d9d11265d7 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11294eaa580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14a47c02580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8676ab01a8b8/disk-a95f71ad.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e3314e350353/vmlinux-a95f71ad.xz kernel image: https://storage.googleapis.com/syzbot-assets/6e2905ccbd1e/bzImage-a95f71ad.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/94e3ac0ab12f/mount_0.gz fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=14a88152580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1659aaaaa8d9d11265d7@syzkaller.appspotmail.com INFO: task syz.0.17:5995 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:29024 pid:5995 tgid:5990 ppid:5927 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2923 [inline] start_dirop fs/namei.c:2934 [inline] filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 __do_sys_unlink fs/namei.c:5575 [inline] __se_sys_unlink+0x2e/0x140 fs/namei.c:5572 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6cd2b5c629 RSP: 002b:00007f6cd2195028 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 00007f6cd2dd6090 RCX: 00007f6cd2b5c629 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180 RBP: 00007f6cd2bf2b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6cd2dd6128 R14: 00007f6cd2dd6090 R15: 00007ffd3df50108 Showing all locks held in the system: 4 locks held by pr/legacy/17: 1 lock held by khungtaskd/38: #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:6/783: 3 locks held by kworker/u8:11/1173: 2 locks held by getty/5552: #0: ffff888036cdf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 7 locks held by syz.0.17/5991: 2 locks held by syz.0.17/5995: #0: ffff888034904480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888054ce9c70 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888054ce9c70 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888054ce9c70 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888054ce9c70 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 7 locks held by syz.1.18/6018: 2 locks held by syz.1.18/6022: #0: ffff8880294e6480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888044ea3430 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888044ea3430 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888044ea3430 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888044ea3430 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 6 locks held by syz.2.19/6044: 2 locks held by syz.2.19/6048: #0: ffff8880247b0480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888044c92850 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888044c92850 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888044c92850 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888044c92850 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 3 locks held by syz.3.20/6075: 2 locks held by syz.3.20/6080: #0: ffff888034d36480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888054cee3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888054cee3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888054cee3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888054cee3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 7 locks held by syz.4.21/6113: 2 locks held by syz.4.21/6117: #0: ffff888035624480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888044c9cbf0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888044c9cbf0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888044c9cbf0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888044c9cbf0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 7 locks held by syz.5.22/6147: 2 locks held by syz.5.22/6151: #0: ffff88804c26c480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888044c96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888044c96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888044c96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888044c96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 7 locks held by syz.6.23/6185: 2 locks held by syz.6.23/6190: #0: ffff888025968480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888044e5c010 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888044e5c010 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888044e5c010 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888044e5c010 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_unlinkat+0x2ad/0x610 fs/namei.c:5521 3 locks held by udevd/6219: 5 locks held by syz.7.24/6221: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 783 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:__local_bh_enable_ip+0x1c2/0x2b0 kernel/softirq.c:307 Code: f7 89 df e8 60 01 00 00 41 f7 c4 00 02 00 00 74 05 e8 52 60 44 00 9c 58 a9 00 02 00 00 75 23 41 f7 c4 00 02 00 00 74 01 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d e9 c0 d7 9d 09 cc 90 0f 0b 90 e9 66 fe RSP: 0018:ffffc900046ffa58 EFLAGS: 00000206 RAX: 0000000000000006 RBX: ffffffffffffffe8 RCX: 0000000000000046 RDX: 0000000000000006 RSI: ffffffff8d55b178 RDI: ffffffff8ba64380 RBP: 1ffff11004a23cc4 R08: ffffffff8f6a23b7 R09: 1ffffffff1ed4476 R10: dffffc0000000000 R11: fffffbfff1ed4477 R12: 0000000000000286 R13: dffffc0000000000 R14: ffff88802511e624 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888126442000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fb63fff CR3: 00000000354ae000 CR4: 00000000003526f0 Call Trace: local_bh_enable include/linux/bottom_half.h:33 [inline] spin_unlock_bh include/linux/spinlock_rt.h:116 [inline] __batadv_dat_purge+0x344/0x400 net/batman-adv/distributed-arp-table.c:185 batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:204 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup